A new modelling study reported in The Lancet Diabetes & Endocrinology has estimated that a total of 355,900 new childhood and adolescent cases of type 1 diabetes occurred in the year 2021; however, only a little over half of them were diagnosed.¹

Ward et al developed a microsimulation model to analyse the natural history and diagnosis of type 1 diabetes in children and adolescents in 200 countries. The model accounted for the variations in the incidence of type 1 diabetes and health system performance in different countries. An open population of children and adolescents was followed every month. The model simulated the incidence and progression of type 1 diabetes including various factors in the health system that may have an impact on the diagnosis of the condition. Data on the incidence of type 1 diabetes, islet cell autoantibody (iAb) profiles and prevalence of DKA from 1990 to 2020 that had been published earlier was used to calibrate the simulation model.

The objective of this study was to estimate the total global incidence of type 1 diabetes and the number of cases that were diagnosed through the use of a structural modelling approach. The incidence indicators of childhood type 1 diabetes from 1990 to 2050 for each country were also projected. Its predictive accuracy was examined by using a randomly sampled test set of data that was not included in the calibration of the model.

An estimated 355,900 new cases of type 1 diabetes among children and adolescents were detected globally in the year 2021, which is much higher than the 149,500 new cases estimated by the IDF Atlas in the same year and 193,516 new cases estimated by another modelling study by Gregory et al.

Out of the 355,900 new childhood and adolescent cases detected, only 200,400 had been diagnosed. A marked variation was seen in the underdiagnosed cases by region, with over 95% of new cases diagnosed in western and northern Europe, North America, Australia and New Zealand but less than 35% of the new cases that were diagnosed in south and south east Asia, west Africa and Melanesia. The model also projected the total number of new cases of type 1 diabetes in children to increase to 476,700 in 2050. According to this study, Africa would have the highest number of new cases and account for 51% of the new cases by 2050.

The prevalence of type 1 diabetes is increasing worldwide. The findings of this study show that the total global incidence of childhood and adolescent type 1 diabetes is much higher than that estimated to be now and there is a marked difference in the different parts of the world. Nearly one in two children, according to this simulation analysis, remain undiagnosed. In view of the projected rise in the incidence of new cases globally, the authors advocate enhanced capacity building of healthcare systems for timely detection and management of type 1 diabetes as more than 80% cases are projected to occur in the low- and middle-income countries, which are already resource crunched. Often, many undiagnosed cases may present with diabetic ketoacidosis, which may be potentially fatal. These findings also call for improving awareness among the general public about the signs and symptoms of type 1 diabetes.

Reference

1. Ward ZJ, et al. Estimating the total incidence of type 1 diabetes in children and adolescents aged 0-19 years from 1990 to 2050: a global simulation-based analysis. Lancet Diabetes Endocrinol. 2022 Dec;10(12):848-858. doi: 10.1016/S2213-8587(22)00276-5.